Now, a jake brake that kills a cylinder often used on semi's is a different matter. Yes, I know the terminology of jake brake vs. exhaust brake, but for the purposes of this discussion you cannot hear my exhaust brake at all.

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With all due respect this is a misconception shared by lots of people because for years they've heard the roar of dumptrucks with unmuffled Jake (compression) brakes. My highly muffled Jake hardly makes any more noise than does my diesel itself; an inexperienced observer wouldn't even notice the difference. Many towns that have engine brake ordinances nuance them so they read "unmuffled engine brakes" prohibited.

As for the OP, his exhaust brake doesn't make the same sound as a compression brake, anyway. So your remark is not relevant to him.

I agree with docj. An exhaust brake particularly has actually lower exhaust flow with the brake active because it is a valve in the exhaust downstream from the turbo. A true Jake compression brake on a fully muffled diesel is not noticeably louder, it just has a different tone. I understand about the sound of an unmuffled Jake as many dump trucks run but a typical motorhome installation would be very hard to detect.

Steve Ownby
Full time since '07

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Steve Ownby
Full time since 2007
2003 Monaco Signature

It's not a misconception to me. Thanks for telling me I'm wrong without knowing anything about me.

As someone that used to live in a town that had a "No engine or exhaust brake use" ordinance and near a major artery where folks used their engine/exhaust brakes often, and I worked graveyard shift. The remark is relevant, to someone, but will you know who that person is? When I was trying to sleep so I could work all night, I knew who that person was: me. Is being considerate to others in the places you go or pass through such an inconvenience or safety risk?

But whatever. Even I try to justify some of the things I do by explaining that I don't do X like everyone else, but I'm still doing something that I probably should not be, or do not need to be doing.

With all due respect, you are confusing an exhaust brake with an engine brake that kills a cylinder.

Come on guys. An exhaust brake does NOT make the noise that a compression brake does. A muffled compression (engine) brake does not make the noise that an unmuffled comp brake does. The ordinances (signs) are meant to limit noise for the sake of local inhabitants. A real concern for the inhabitants. (We won't wonder why they bought a house near a hill if they wanted peace and quiet)! Any increased noise from an exhaust brake is usually caused by downshifting and running at higher rpm. They can't regulate (nor should they) shifting patterns on a hill.

No, I'm not confusing one for the other. I have a Class A CDL with all available endorsements, and have driven vehicles with Jacobs Engine Brakes, various other brands of engine compression brakes, exhaust restriction brakes, fluid restriction braking systems, magnetic systems, and rigs without supplemental braking systems at all.

Exhaust brakes can be more quiet than compression, but still make extra noise compared to not using them. I can hear a rig coming down a hill and tell the difference between exhaust and compression, but they still make extra noise.

Some folks claim they cannot hear their exhaust brake, but maybe they just can't hear it over their even louder engine/radiator fan. I claim they may not hear as well as I do. Others may simply be delusional. They make extra noise, and as I said earlier, I am not surprised when folks do something to explain about why it's OK for them to do it when maybe they should not.

Is courtesy to the people that live where you pass through or visit so damned difficult? I guess maybe it is.

Don't wake me up with your supplemental brakes, loud exhaust, or excessive idling. I become extra unfriendly when woken up for useless and unnecessary reasons, especially when you try to tell me you needed that "extra safety margin" on a dry, clear day with plentiful sunshine. It's pure selfishness, ignorance, you aren't driving safely to begin with, or some combination thereof.

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ORV 19B Full Timer, '14 Ram 2500 Diesel and a GSD. This signature updated, March 27, '18.
Currently working around Redmond OR de K7NOL 146.52Mhz Safety? (CLICK ME!)

With all due respect this is a misconception shared by lots of people because for years they've heard the roar of dumptrucks with unmuffled Jake (compression) brakes. My highly muffled Jake hardly makes any more noise than does my diesel itself; an inexperienced observer wouldn't even notice the difference. Many towns that have engine brake ordinances nuance them so they read "unmuffled engine brakes" prohibited.

As for the OP, his exhaust brake doesn't make the same sound as a compression brake, anyway. So your remark is not relevant to him.

I think you have to use your common sense and discretion when reading the signs posted for engine brakes. Unless it specifically says un-muffled engine brakes it would refer to all engine braking as being prohibited.

Then again it would depend upon the discretion of the officer who stopped you (if indeed they did). Now days with the economy as it is and the idea of revenue generation it could be chancy. Not that revenue generation is occurring!

Many locations, especially urban, prohibit the use of engine or exhaust brakes, and usually post signs to that affect. I've also seen those signs posted on interstates in urban areas.

There used to be a sign on I90 going through a canyon that banned the use of engine and exhaust brakes for a few miles in the ID panhandle. I think it was near Wallace or Silverton? I was surprised to see it, but just slowed down, downshifted when necessary, took it easy on the brakes, increased following distance, and cruised through as quiet as I could. It was easy and safe to deal with.

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ORV 19B Full Timer, '14 Ram 2500 Diesel and a GSD. This signature updated, March 27, '18.
Currently working around Redmond OR de K7NOL 146.52Mhz Safety? (CLICK ME!)

Rather than trading anecdotal factoids, here's a quote from a technical paper on the topic:

Truck, engine and equipment manufacturer studies have consistently found that improperly muffled vehicles are the root cause of this noise issue. Vehicle operating sound levels have been shown repeatedly to be much higher for vehicles with improper, defective or deteriorated mufflers. The problem is most pronounced on vehicles equipped with “straight stack” exhaust systems (i.e., no muffler). Studies have found that the sound level from “straight stacks” is 16 to 22 dB(A) higher than from original equipment mufflers. Studies have also shown that the operation of an engine brake produces sound levels that are similar to those produced during acceleration
on properly muffled vehicles.

And, yes, the paper was published by Jacobs Vehicle Systems, the principal manufacturer of compression brakes, but just because its author has a bias doesn't make it wrong.

Another key point of the paper is that:

All new vehicles must comply with EPA noise regulations. The maximum permitted noise level was set to 83 dB(A) in 1979 and later reduced to 80 dB(A) in 1988. The overall design and manufacture of heavy-duty trucks, including their exhaust systems, results in all new vehicles meeting the applicable regulations when they leave their manufacturer’s factory.

The EPA regulations prohibit “The removal or rendering inoperative by any person, other than for purposes of maintenance, repair, or replacement, of any device or element of design incorporated into any new vehicle for the purpose of noise control prior to its sale or delivery to the ultimate purchaser or while it is in use”. The EPA regulations also prohibit the use of a vehicle that has had the noise control system rendered inoperative. This is stated clearly on a label required on all vehicles s old in the U.S. and is fully explained in the operator’s manual for every new truck.

The improperly muffled vehicles, especially those with straight stacks, are not operating in compliance with current federal regulations. Most states have adopted motor vehicle regulations that address the configuration and condition of vehicles operated on their roads and highways. These regulations typically require that a vehicle be equipped with a proper exhaust system and a muffler. “Straight stacks” are not in compliance with either the federal or the state regulations.

The bottom line is that a properly configured heavy vehicle (including a motorhome) will meet the appropriate noise standards even when its engine brake is engaged. IMHO most communities that post "engine brake use prohibited" ordinances are trying to prevent straight stack use by truckers and aren't out to get the passing motorhome. I could be wrong, but I'll take my chances.

I have it on all the time but I live out west and it seems I am always on hills.

As far as the noise, I have only seen signs that restrict engine brakes which are a different beast than exhaust brakes. If I saw a sign for exhaust brakes, I would turn it off. I am not sure why there would be a sign for exhaust brakes since the ones I have are really not noisy. I do see where they may reduce mileage since they engage each time you take your foot off the accelerator.

If you have an exhaust brake called a Pac Brake, be sure and lubricate it once per year. There is a good picture in the Freightliner maintenance manual that shows the Pac Brake and how to lubricate it. There is a special lubricant for Pac brakes. We have to open the hatch in our bedroom to access it.

Yes, I meant exhaust break, not air break. Sorry about that. I did notice that every time I let-up on the gas the break would engage so for now I'm learning to just use it when I encounter bigger hills.

Yes, I meant exhaust break, not air break. Sorry about that. I did notice that every time I let-up on the gas the break would engage so for now I'm learning to just use it when I encounter bigger hills.

Pexring,
As stated earlier, it's no big deal. It's just that in the future, if you still have issues or, need to know more about the operation of your EXHAUST BRAKE, then it pays to put down the correct terminology. All this talk about Exhaust brakes and "Jake" or, Compression brakes is amazing. No, one cannot hear an "EXHAUST BRAKE". But, you can hear a Jake or Compression brake.

All one is hearing when an EXHAUST brake is used, is the engine fan pushing more air, due to the fact that that when the exhaust brake takes effect, the transmission is talked to by the engine ECM and, both are reading the road speed and the engine speed and, if all conditions are met, then a downshift is presented and, with that, higher engine RPMs and, that brings higher fan RPM which brings simply MORE AIR NOISE, not ENGINE COMRESSION NOISE.

But, in the case of a COMPRESSION BRAKE, the engine is building a "compression stroke" and, at the last minute, the exhaust valve is opened and, all that compression is released WITH0UT any fuel jettisoned into the cylinder as it would normally. So, yes, you would hear that. But, as has been stated a few zillion times, todays mufflers on motor homes are seriously more quiet than the old yesteryear dump/hauling/18 wheeler/cement/ and any other COMPRESSION BRAKE equipped truck.

Confusing higher fan noise with an EXHAUST NOTE is well, apparently something that cannot be understood by some.
Scott